Such a blow unit is known from practice and is for instance disclosed in WO 2006/101391 A1 of applicant. The known blow unit comprises a body that is attachable to a pump unit for supplying gas, an outlet opening in said body for delivering the supplied gas to the film material passing the outlet opening. The blow unit may further comprise a guiding element that is adapted to guide the film material such that the outlet opening and the film material are positioned with respect to each other in a predetermined way. Furthermore, the blow unit may comprise a cutting element, such as a knife for cutting the film material. The known blow unit can be used in an apparatus for making air-filled bags from a film material comprising chambers. The film material may for instance be a tubular foil having two longitudinally extending edges, the tubular foil further comprising transverse rows of perforations located at mutual distance to form the different chambers. Transverse welds may be arranged on either side of every transverse row of perforations at a short distance thereof. With such a foil material, air can be introduced into the chambers via a mouth of the chamber that extends in between two transverse welds. The guiding element of the blow unit enters the chamber adjacent the first of the two opposing transverse welds. The cutting element, for instance a knife, cuts the longitudinal edge of the tubular foil adjacent the blow unit such that the tubular foil can pass the outlet opening of the blow unit. Via said outlet opening, air is introduced in the inner space of the chamber that is enclosed by the other one of the longitudinal edges and the two opposing transverse welds. After completely filling the chamber with air, the chamber is sealed by means of a sealing unit arranged downstream of the blow unit.
Developments in the air-filled cushion packaging material industry demand for increasingly faster apparatuses for making air filled cushions from different kinds of film material having different kinds of cushion configurations. Such apparatuses also need to be able to make air-filled cushions from relatively thin, and thus relatively inexpensive, film material, without increasing the risk of damaging the film material. This is especially important when an apparatus has to be re-adjusted often to be able to change between different film materials, having different configurations and/or having a different film material thickness during a short period of time. This may for instance occur in large distribution companies or smaller companies that aim at packing different kinds of products in different kinds of packaging.
A disadvantage of the known apparatus having the known blow unit is that when using another kind of film material for instance with relatively complex configurations, thus a complex pattern of welds and seals, for instance comprising multiple transverse and longitudinal rows of relatively little cushions for instance separated by longitudinal rows of point seals and multiple transverse welds extending at mutual little distance, the known blow unit is not able to produce air-filled cushions with a sufficient filling degree. When introducing air via the outlet opening in the inner spaces of the respective cushions in a first transverse row of cushions, only the cushions most adjacent the outflow opening are filled in the predetermined time with the predetermined filling degree. If the predetermined filling degree has to be obtained, the filling time will increase and the film material may be damaged.